Before traveling to New York City in 1976, Andreas Adam’s only knowledge of the metropolis was from his collection of postcards.

A Switzerland-born resident of London, Adam started amassing postcards of skyscrapers from flea markets in 1971, after earning a degree in architecture. His interest in collecting iconic buildings like Park Row and Flatiron turned into fanaticism, and he expanded into greeting cards and tourist staples like the Statue of Liberty and Ellis Island. His new book, “New York in Postcards 1880-1980,” features his rare collection of vintage postcards.

“One postcard is like a single mosaic stone in a larger mosaic of history,” Adam said in an interview. “The value of the collection is not that I have thousands of postcards but that I can put it in a certain context that shows the history of New York.”

The book, which will be released Friday, lays out nearly 1,000 postcards of New York by theme, from the slums of the Lower East Side to public buildings from the early 1900s like the post office and city jail. Others depict the formative era of Wall Street and early “I Love New York” postcards from the 1970s.

“The changes of the motifs represent the change of the values of the city in some way,” Adam said. Postcards “give you a look at what was a sensation at the time.”

Adam, who now lives in Zurich, stopped collecting in 1980, when some of his postcards were featured in an exhibition at a Switzerland museum. In just nine years, he managed to accumulate some 4,000 postcards of New York City.

“It was like a finished book after 1980,” Adam said. “I’m no longer the fanatical collector.”

Adam doesn’t know the monetary worth of his postcards. He prefers to discuss the emotional value the images. “For instance,” he explains, “if you have a postcard of Ellis Island which only shows the building, it’s not as interesting as an immigrant who is looking from Ellis Island to Downtown Manhattan in the same picture.”

He doesn’t care for modern postcards, dismissing most as “very banal photographs.” But sometimes even an unappealing example has value. “An ugly postcard may be very interesting because it shows how beautiful the others are,” he says. “Sometimes you need something ugly or banal to see the value of other things.”

Corrections & Amplifications:Andreas Adam lives in Zurich and began collecting postcards in London. An earlier version of this story incorrectly stated that he lives in London